Belt machine



y 1965 E. s. KUBALA 3,182,572

BELT MACHINE Filed March 16, 1962 4 Sheets-Sheet 1 y 1965 E. s. KUBALA 3,182,572

BELT MACHINE Filed March 16, 1962 4 Sheets-Sheet 2 E. S. KUBALA May 1 l,'\ 1965 BELT MACHINE 4 Sheets-Sheet 3 Filed Marc h 16 y 1965 E. s. KUBALA 3,182,572

BELT MACHINE Filed March 16, 1962 4 SheetS Sheet 4 N {A h a Q: a 8:

Q m L]- b\ United States Patent 3,182,572 BELT MACE Elisha S. Kubala, 1439 NE. 29th St., Oklahoma City 11, Okla. Filed Mar. 16, 1962, Ser. No. 180,258 11 Claims. (Cl. 94-45) This invention relates to paving apparatus and more particularly it relates to a machine for smoothing away irregularities in the surface of freshly laid concrete.

For many years concrete contractors have dragged a wide, heavy belt back and forth across freshly laid concrete as the final finishing step before the concrete hardened, with the minor exception perhaps of spot finishing occasional blemishes of an especially troublesome nature. The belt was usually longer than the width of the pavement. It was utilized by laying it transversely on the concrete strip and reciprocating it over the strip while moving it a short distance forward along the strip with each stroke. With the belt it was found that a much larger area of concrete could be satisfactorily finished in a given time than could be finished by a large number of workmen finishing the entire surface with small hand tools.

The operation employing the belt is known as belting. In earlier times the operation was performed with a long flat belt with a handle at each end to enable the belt to be dragged back and forth across the concrete by two men. More recently, man-power has been replaced by motor-driven machines which can be operated by one man and which take the back-breaking labor out of this operation. These machines were designed for belting flat slabs of concrete such as are used in highway and airfield construction, where there are no curbs in place and the surface of the concrete is even with the tops of the forms. They could also be utilized in the old style of street construction in which the curbs were poured only after the load-bearing surface of the street had been completed.

New methods of street construction have created a need for improved belting machines. Recently, it has been found desirable for various reasons to install the curbs of streets prior to or practically simultaneously with the pouring of the concrete for the load-bearing portion of the street. Known belting machines were not adequate for use in connection with this newer mode of street construction since no way couid be found to operate satisfactorily upon streets having curb forms or preformed curbs which are necessarily elevated above the street level and would consequently interfere with a belt that is longer than the width of the shtreet.

The principal object of the present invention is to provide an improved machine for belting purposes. Further objects include the provision of means: for smoothing freshly laid concrete where curbs or curb forms are already is place; for performing the same work where no such curbs or curb forms are in place; for smoothing surface of freshly laid concrete strips of any width-within convenient limits-with only a few simple operations being required to effect the necessary adjustment; for smoothing either flat slabs or streets with crowns; and for such other purposes as will become apparent from the following disclosure and the accompanying drawings.

Machines constructed in accordance with my invention will ordinarily include some sort of carriage, that is to say a frame with Wheels or skids or other means of moving the machine along the concrete strip. On the carriage there will be belt mounting units, each of which includes a rockable member having a generally downward facing convex arcuate surface. The rockable members may be installed at a fixed height with respect to the carriage or may be adjustable to different vertical elevations. The

3,132,572 Patented May 11, 1865 machine will ordinarily include only one belt, but more may be added if desired. Each end of the one or more belts will be held by a belt unit, so that each belt is tensioned between two belt mounts which are capable of holding the belt against the pavement, of transmitting driving force to the belt and of absorbing the counterthrust created by the drag of the concrete against the belt as the machine travels and the belt reciprocates.

The machine is provided with means for causing the rockable members at the two ends of every belt to rock in unison so that each belt is smoothely drawn back and forth over the concrete. The last-mentioned means may be a hand-operated mechanical linkage or, preferably, a motor-driven hydraulic and mechanical system, or any other form of power transmission device which would suggest itself to one skilled in the art.

The machine is also provided with means to propel it along the concrete strip. Such means might include handles for men to use in pushing it, or a tow-bar by means of which it could be drawn along behind another machine, or a gasoline engine for self-propulsion, or any other means that one skilled in the art would select as a suitable means of accomplishing the stated purpose.

In order that the above-stated underlying concepts may be considered in connection with a concrete example thereof, a description will be given of that mode of carrying out the invention which the inventor now believes to be the best mode. In the description, reference will be made to the accompanying drawings, in which:

FIGURE 1 is a front elevation;

FIGURE 2 is a top plan view;

FIGURE 3 is a sectional view taken along section lines 3-3 in FIGURE 2;

FIGURE 4 is a top plan view of the subject matter of FIGURE 3 with parts broken out for the sake of clarity;

FIGURE 5 is an enlarged fragment of FIGURE 1;

FIGURE 6 is a side elevation of the subject matter of FIGURE 5 with some parts broken out;

FIGURE 7 is an enlarged fragment of FIGURE 1;

FIGURES 8 and 9 are complementary schematic representations of the motion of the rockable members;

FIGURE 10 is a view of the subject matter of FIG- URE 3, some parts being adjusted to different positions;

FIGURE 11 is a fragmentary view of a modification of the invention taken from the front in elevation.

Throughout the various figures each part retains the same numeral. Reference numerals between 20 and S 9 identify parts which are exact duplicates of parts having the same numerals preceded by the numeral one-that is, between and 199. Parts on the left-hand side of the machine are assigned numbers 20-95 for instance 27. The number 127 refers to a part which is identical to part 27, but which is found on the right side of the machine. Sections are taken in the directions indicated by arrows at the ends of the section lines.

In this embodiment of the invention as shown in FIG- URES l, 2, 3, 4 and 10, the carriage includes 2 wheel assemblies and a chassis. The wheel assemblies are identical mates. Therefore only the left-hand wheel assembly will be described in detail. Where a reference numeral is applied to a part in the left-hand wheel assembly, the same numeral prefaced by a number one is used to identify the same part in the right-hand wheel assembly.

The left-hand wheel assembly includes a chassis 20 supported by wheels 25 and 26 that rest upon a curb form 23, next to which is a freshly poured concrete curb 21 and street surface 22. The wheel assembly includes a stanchion 28 upon which is a propulsion motor 27 adapted to rotate wheel 26 through a sprocket and chain drive 29. Between the wheels are located four vertical posts 30, 31, 32 and 33 which project upwardly from the chassis 253 for supporting the frame of the machine. The above description applies equally well to the righthand wheel assembly.

The frame of the machine includes a main or central portion and side extensions to permit adjustment of the gauge of the machine. The primary structural members are parallel front and rear transverse main frame members 37 and 36, respectively. They are fabricated from channel iron and are reinforced by a center brace 39 as well as by side braces 38 and 138 across the top of the frame. From beneath, the main portion of the frame is strengthened by trusses 52. Between the transverse main frame members 36 and 37 is a center walkway 40. Secured on brackets 42 to rear main frame member 36 is a rear walkway 41. On a supporting framework 45 which bridges frame members 36 and 37 is an operators seat 43 and a control console 44. This completes the main portion of the frame.

The side extensions of the frame permit telescopic adjustment of the over-all width of the frame. The frame extensions include front extensions 46 and 146, rear extensions 47 and 147, and end sections 48 and 148, all of channel iron stock, but of a slightly larger size than the main frame members 36 and 37. Thus the rear main frame member 36 is nested in rear extensions 47 and 147 while the front main frame member 37 is nested in front extensions 46 and 146. The outer ends of extensions 46 and 47 are both attached to end section 48. End section 148 and extensions 146 and 147 are also connected with one another in the same manner. The extensions are provided with a series of uniformly spaced bolt holes and 150. Series of the same size holes are also provided on the main frame members 36 and 37. The bolt holes in the main frame members are partially obscured in the drawings by the frame extension members which overlie them. Those which do show are numbered 49 and 149. In order to fix the frame of the machine at any width between the limits dictated by the locations of the holes and by the length of the main frame members and extensions, it is necessary only to line up the proper holes in the series 49 and 149 with the corresponding holes in the series 50 and 150 and fasten the parts together with nuts and bolts 51, as is shown in FIGURES 1 and 2.

The means for attaching the frame to the wheel assemblies so as to permit vertical and lateral adjustment thereof will now be described with particular reference to FIG- URES 3 and 4. FIGURE 3 is a sectional view based upon FIGURE 2. In FIGURE 3, the posts 31 and 33, which were previously described as projecting upwardly from the chassis 20, are shown to be bolted to two horizontal bars 59 and 60 cut to length from angle stock. Each of the said posts has four uniformly spaced holes 66 and there are holes with the same spacing in bars 59 and 60. Thus, with the aid of bolts 64, the bars 59 and 63 can be secured to the posts 31 and 33 at any one of three possible elevations. The posts 30 and 32 are secured in a similar manner to two other bars 57 and 58 which are hidden in FIGURE 3. See FIGURE 4. Bar 58 is directly below bar 57 and would be completely hidden by it in FIGURE 4 were it not for the small broken out portion of bar 57 in the illustration.

The pieces of angle stock mentioned above are welded at each end to two short lengths of channel stock and 56 which are of a size selected with the specific purpose of fitting neatly inside the frame extensions 46 and 47. No attempt is made here to fasten the parts 55 and 56 to the frame extensions. Instead, the aforementioned pieces of angle stock, 55, 56, 57 and 58, are cut to that length which will bring parts 55 and 56 almost into direct contact with extensions 46 and 47 respectively. Because they are held within the confines of frame extensions 46 and 47, the short channels are in position to carry the weight of the main frame of the machine which is transmitted by them, in turn, to the bars 57, 58, 59 and 60, to the posts 30, 31, 32 and 33, to the wheel assembly chassis 20, to the wheels 25 and 26, and to the forms. Also, because of their manner of installation, the short channels and the bars fastened between them constitute a movable sub-assembly which is able to slide laterally in the frame. Since the wheel assembly is secured to this sub-assembly through posts 30, 31, 32 and 33, the wheel assembly also moves laterally with the sub-assembly. Such lateral movement is controlled by the adjusting screw 62.

The adjusting screw passes through the end section 48. It is restrained against axial movement with respect to part 48 by its own head on the one hand and by a collar on the other. However, the screw is free to rotate and its threaded end engages a correspondingly threaded thrust plate 6-1 which is welded directly to the bars 57 and 58, which are in turn fastened to channels 55 and 56, to the posts 30, 31, 32 and 33 and to the remainder of the Wheel assembly. Thus the left-hand wheel assembly moves laterally only as the adjusting screw 62 is turned. All that has been said with respect to the mounting and lateral adjustment of the lefthand wheel assembly with respect to the left end of the frame applies equally well to the mounting and adjustment of the right-hand wheel assembly on the righthand end of the frame.

The frame, the wheel assemblies, the various means for adjusting their relative positions and other parts mentioned above constitute the carriage of the machine. The carriage serves as a mobile support for the power plant, for the operator, for any hand finishers who may ride the machine from time to time to give special attention to any particularly troublesome irregularities in the concrete surface, and for the concrete smoothing belt. The belt 69 is suspended from the carriage by a pair of belt mounts, one on each side of the carriage near and just inboard of the wheel assemblies. Only the left-hand belt mount will be described in detail since the right-hand belt mount is identical to it.

The left-hand belt mount, as shown in FIGURES 5 and 6, includes a vertical trackway 70 which is secured to frame extension 46 with the aid of upper and lower retainers and 76, which are permanently fastened to the back of the trackway. The retainers are not fastened directly to the frame members 46, but instead furnish a base to which clasps 77 may be bolted with the aid of bolts 78. When the bolts are tightened, the frame extension is gripped tightly between the clasps 77 and the back of the trackway 70. In this manner a tight frictional engagement is obtained between the trackway and the frame, preventing longitudinal and lateral movement of the trackway. The retainers, of course, prevent vertical and rocking movement of the trackway. In this manner, the trackway 70 is fixedly secured to the carriage of the machine. To laterally adjust the position of the belt mount it is necessary only to loosen the bolts 78, slide the trackway laterally to the desired location and retighten the bolts.

Within the trackway is a rectangular slide member 71. Its position is maintained and adjusted with the aid of worm 72, nut 73 and crank 74. The worm 72 with crank 74 attached to its upper end is mounted in the top of trackway 70 where it is free to rotate but is not free to move axially, either up or down. The screw is threaded into the nut 73, which is fixed on the front face of the slide member. Thus, the slide member 71 will move up or down only when the crank 74 is operated. This makes it possible to adjust the slide to any given height within the limits of trackway 70 and to maintain the setting indefinitely.

Also on the front face of the slide at its lower end, as shown in FIGURE 6, is a shaft means 79 which projects forwardly and generally parallel to the surface of the pavement. The shaft serves as a pivot point for a rockable member through which the belt 69 is attached to the belt mount and the carriage. The rockable member includes a hub 81 which permits the rockable member to rotate on the shaft means 79. A disc 80 having a lower circular portion is mounted on the hub. To the circular portion of disc 80 is secured a member which includes a generally downwardly oriented convex arcuate surface 82. In this embodiment, the surface 82 is a halfcylinder with its convex portion facing downward and its straight edges oriented perpendicular to the line along which the belt reciprocates. The belt is fastened to the rockable member in such a fashion that that portion of the belt nearest its end is stretched over part of surface 82. In this embodiment, the belt is fastened to the outer edge of the surface 82 with nuts and machine screws 83.

To the upper portion of the disc 80 are secured a pair of levers 84 which converge at their upper ends. At this convergence is a small block 85 which carries a ball bearing pivot in which a short stub shaft 95 is retained in such a manner that it may rotate without substantial axial movement. The shaft 95 is the means by which the rockable member and the belt are connected to the driving means.

All of that which has been said with respect to the lefthand belt mount and its rockable member applies equally well to the right-hand belt mount and its rockable memher. The object of providing the driving means is to make it possible to rock the left-hand and right-hand rockable members substantially in unison, so that the belt may be caused to reciprocate back and forth over the concrete surface. In this example of how my invention may be embodied, the driving means includes, as shown in FIGURE 7, a main driving wheel 86, rotatably mounted on a shaft 87 which is journalled in ball bearings (not shown) attached to the frame of the machine. Projecting forwardly from driving wheel 86 is an eccentric crank 89, upon which is mounted a cross-head 91.

The cross-head is a rectangular plate provided with a bearing and retainer 99 which allow rotational but not axial movement of the cross-head with respect to eccentric crank 89. Main driving rods 92 and 192 are pivotally attached to diametrically opposed points on the cross head. The main driving rods 92 and 192 are connected to driving rod extensions 93 and 193, respectively, and the latter are connected to the stub-shafts 95 and 195 on the left and right-hand rockable members. The main driving rods and their extensions are each provided with a series of uniformly spaced holes which may be matched with one another to provide any desired over-all length, within limits. Machine screws 94 and 194 are inserted in the matched holes and are retained in position with nuts and lockwashers.

In order to prevent unwanted rotation of the crosshead with respect to the driving rods and at the same time provide for adjusting the tension on the belt, a cross head adjuster 96 is furnished. It cooperates with a short post 97 projecting upwardly from main driving rod 192 and having a hole therein to receive the threaded end of the adjuster 96. Its other end is secured to the cross-head 91 at a point between where the main driving rods 92 and 192 are pivotally secured to the cross-head. The adjuster 96 is prevented from moving with respect to the post 97 by lock nuts 98 on each side. By changing the positions of the nuts 98 it is possible to draw both driving rods inward at the same time, rotating the arcuate surfaces 82 and 182 outward simulaneously and thus stretching the belt. By a reverse procedure it is possible to slacken the tension on the belt. When the adjuster is locked against movement with the belt under the desired tension, the total effective length of the driving rods 92, 192 and their extensions 93, 193, is held constant, or very nearly so,

as the main driving wheel 86 rotates. Therefore, rotation of the wheel 86 will cause the driving rods to move substantially in unison, causing both the rockable members to rock first to the left, then to the right substantially in unison, as indicated in FIGURES 8 and 9. A counterweight 90 is provided on wheel 86 to balance the mo- V 6 ments of the crank 89, cross-head 91, adjuster 96, driving rods 92 and 192 and other parts which are centered or arranged about the shaft 87. As a result, continuous rotation of the wheel 86 on shaft 87 will produce a smooth, continuous reciprocation of the belt 69.

As shown in FIGURE 7, a single power plant is provided to drive the belt driving wheel 86 and to drive the propulsion wheels in the wheel assemblies. The prime mover is a small gasoline engine 200, mounted on the carriage. It drives a hydraulic pump 201, also mounted on the carriage, through a multiple V belt and gangedpulley drive 207. The pressure side of the pump is connected to the control valves 203 on the operators console 44 and to a pressure regulator 202 which is vented back to a reservoir 209 from which the pump continuously withdraws fluid. The valves 203 are operable to send hydraulic fluid under pressure at any desired rate to the belt drive motor 205 and the propulsion motors 27 and 127 through conduits 204. The low pressure sides of the motors are connected back to the reservoir.

The belt drive motor 205 is supported above the frame on a motor stanchion 208 which stands near the belt driving wheel 86. By means of a chain and sprocket drive 206, the motor shaft is operatively connected to the driving wheel. Through this connection the motor is able to drive wheel 86, the rockable members and the belt 69. This completes the description of an operative embodiment of the invention.

The above embodiment is particularly useful in the smoothing of surfaces of freshly poured concrete streets, where, as shown in FIGURES 1 and 3, curbs and curb forms are already in place. It will now be shown how by a simple modification the above embodiment can be converted for use on sl-abs without curbs or curb forms in place. The belt 69 is removed, as are the two belt mounts by removing the fastenings 78, 178, 83 and 183. Next, the carriage is raised by removing the fastenings 64, by raising the carriage so that the upper pairs of holes 66 in posts 30, 31, 32, 33 match the holes in parts 57, 58, 59 and and by reinserting the fastenings 64. Compare FIGURES 3 and 4 with FIGURE 10. It should be understood that the same operations will be performed upon the right-hand wheel assembly at this time.

The above operations having been completed, the wheel assembly adjusting screws 62 and 162 are turned in the direction necessary to move the wheel assemblies as far inward as possible. Turning is continued until the threads on the adjusting screws disengage themselves from the threads in the thrust plates 61 and 161. Then the wheel assemblies may be freely shifted toward the center of the carriage until they are separated by that distance which corresponds to the gauge of the forms in which the concrete is to be poured. When properly positioned, the wheel assemblies should be secured to the frame in any suitable manner, such as with a C clamp 210 to prevent further lateral movment. With the wheel assemblies clamped in place, the belt mounts may be installed on the frame again in the same manner as before, but outside the wheel assemblies. The belt 69, or a longer. one if necessary, may then be secured to the belt mounts in the same manner previously explained. The modified form just described is shown in FIGURE 11, which shows only the left end of the machine. The appearance of the center of the machine as modified will be identical to the first embodiment as it is illustrated in FIGURE 7; the right end of the machine, as modified will have the same appearance as the left end, shown in FIGURE 11, except that the positions of the parts in FIGURE 11 will be reversed, like the image in a mirror.

The operation of the two embodiments described above is substantially the same, except as noted hereafter. In operating the machine to finish a strip of concrete, assuming a paver has already laid a partially smoothed bed of concrete between side forms in the usual manner: the belt machine is set on the forms, spanning the strip, with the flanged wheels 25, 26, 125 and 126 adjusted to proper width for riding upon the forms; the cranks 74 and 174 are rotated until the arcuate portions 82 and 182 of the belt mounts are at just the proper height to bring the belt evenly into contact with the concrete all the way across; the belt tension is adjusted; and the machine is started forward over the concrete.

The correct belt tension is a condition best judged by observation. It will generally be observed that the belt tension may be very great where the machine is operating on a fiat surface, such as is shown in FIGURE 11. On the other hand, where the machine is employed in the finishing of cambered or crowned streets as shown in FIGURE 1, the belt tension should be reduced. Otherwise the belt will tend to dig into the surface of the work it has just finished when it is driven backwards for the purpose of starting a second pass over the same stretch of pavement. When the tension is set correctly for crowned streets, the belt tends to bow slightly in the horizontal plane in a direction opposite to the travel of the machine at the particular time. The operator will readily become accustomed to setting the tension of the belt by operating the adjuster 96 until the belt is observed to bow properly on a cambered pavement.

The operator sits upon the seat 43 and operates the various valves 203 on the operatorsconsole 44. These valves independently control the speeds of the two Wheel motors 27 and 127 and the speed of the belt motor 265. Another valve controls'the direction of movement of the carriage, forward or reverse. By manipulating these valves the operator controls the number of times the belt reciprocates per minute. He can guide the machine through curves of short radius by running the propulsion motor on the outside wheel assembly slightly faster than the motor on the inside wheel assembly. Thus the machine travels under power along the curbs and/or forms with the belt reciprocating, the operator operating the various valves to keep the machine moving on a true course and at the proper rate of speed. As the machine moves along the strip, the reciprocations of the belt, when it is properly adjusted, will produce a very smooth surface which will require a minimum of touching-up and spot finishing.

The above-described embodiments illustrate some of the numerous advantages of this invention. First, the machine can operate where curbs and/ or curb forms are in place. It can smooth the concrete to within a very few inches of any curb which may already be in place, reducing hand finishing to a minimum. It has been shown in FIGURES 10 and 11 how the machine may be converted to use where there are no curbs with a few simple operations. It has been shown how a coarse adjustment of carriage width can be obtained by manipulation of the fastenings between the main frame members 36 and 37 and the frame extensions 46, 47, 146 and 147. Finer adjustment of the gauge of the wheels has been demonstrated as being possible with the aid of adjusting screws 62 and 162. The embodiments demonstrate that the belt mounts may be shifted laterally by loosening the fastenings 78 with the result that longer and shorter belts may be accommodated. It has further been illustrated how the belt elevation with respect to the carriage can be adjusted with the aid of cranks 74 and 174. The embodiments also include means for adjusting belt tension, the adjuster 9.6 and lock nuts 98. Finally, it has been shown how the relative height of the wheel assemblies may be varied with respect to that of the frame by transferring the fastenings 64 from one pair of holes 66 to another pair.

Each of the above-named adjustments and alternate positions for the various parts of the machine have some usefulness. However, the inventor is aware that some or perhaps all of these adjustments might be omitted, or combined with .01 another for purposes of making the machine even simpler and more economical to construct and operate. It is even possible that some adjustments or accessories might be added to the embodiments illustrated. Changes might be made in the details of construction such as the manner of fastening certain par-ts together, the substitution of one structural shape for another, the substitution of one type of power plant or driving means for another and an almost endless variety of other changes falling within the skill of the art. All of the omissions, additions, changes and substitutions mentioned above as well as others not specifically mentioned clearly fall within the scope of the present invention and the appended claims are intended to cover them.

Having described my invention, I claim:

1. A machine for smoothing the surface of a strip of concrete freshly laid between forms, said machine being characterized by:

(a) a pair of transversely spaced wheel assemblies, each having its own independent motor means and being adapted to travel along such forms, and a frame supported upon said wheel assemblies to thereby form a carrriage adapted to extend across and above such a strip;

(b) spaced apart belt mounts dependent from said frame, each of said belt mounts including forwardly projecting shaft means extending from said belt mounts in a generally horizontal plane and a rockable member journalled on said shaft, said rockable member including a hub portion, a vertically disposed disc centered upon and secured to said hub portion, said disc having a circular lower portion, and a generally downwardly disposed convex arcuate surface supported by said disc along the circular portion thereof;

(0) a concrete smoothing belt secured to the arcuate surface of each of said rockable members and adapted to rest on the surface of such a strip;

(d) driving means mounted on said frame and connected to said rockable members for rocking said members substantially in unison whereby said belt is reciprocated back and forth.

2. A machine for smoothing the surface of a freshly laid concrete strip, characterized by:

(a) a pairof transversely spaced wheel assemblies each adapted to travel along one side of such a strip and a frame extending between said wheel assemblies to thereby form a carriage;

(b) spaced apart belt mounts dependent from said frame, each of said belt mounts including substantially parallel shaft means extending from said belt mounts in a generally horizontal plane and a rockable member journalled on said shaft, said rockable member having a generally downwardly disposed convex arcuate surface;

(0) a concrete smoothing belt secured to the arcuate surface of each of said rockable members and adapted to rest. on the surface of such a strip;

(d) driving means mounted on said machine and interconnecting said rockable members for rocking said rockable members substantially in unison.

3. A machine as in claim 2 wherein said belt mounts each include a generally vertical trackway, a slide member adapted to move up and down said trackway, and means for adjusting the vertical elevation of said slide member, said shaft being secured to said slide member so that the vertical elevation of the belt with respect to the frame and wheel assemblies may be varied.

4. A machine as in claim 2 wherein said carriage includes means for varying the spacing between said wheel assemblies so that the machine may operate over forms of varying gauge.

5. A machine for smoothing the surface of a freshly laid concrete strip, characterized by:

(a) a frame adapted for movement over said strip;

(b) belt mounts secured to said frame, each of said belt mounts including a rockable member including a generally downwardly facing half cylindrical surface having an outer end;

(0) a concrete smoothing belt stretched between said rockable members and connected to said halfcylindrical surfaces at the outer ends thereof; and

(d) means mounted on said machine and interconnecting said rockable members for causing them to rock substantially in unison.

6. A machine as in claim 5 including self-propulsion means.

7. A machine as in claim 5 wherein means are provided for varying the vertical elevation of the arcuate surfaces of said belt mounts with respect to the carriage.

8. A machine as in claim 5 wherein means are provided for varying the transverse spacing between said belt mounts.

9. A machine as in claim 5 wherein means are provided for varying the gauge of the carriage so that the machine may operate over strips of different widths.

10. A machine as in claim 5 wherein said carriage includes a frame and wheel assemblies and means are provided for varying the relative height of said frame with respect to said wheel assemblies.

11. A machine for smoothing the surface of a freshly laid concrete strip, characterized by:

(a) a frame adapted for movement over said strip;

(b) a plurality of belts mounts carried by said frame, each of said belt mounts including a pivot and a rockable member carried by said pivot, said rockable member having a generally downwardly disposed convex arcuate surface;

(c) a concrete smoothing belt stretched between and secured to said rockable members; and

(d) means interconnecting said rockable members for causing them to rock about said pivot points substantially in unison.

References Cited by the Examiner UNITED STATES PATENTS Re. 18,455 5/32 Carr 94-45 1,410,114 3/22 Peterson 94-44 1,584,385 5/26 Lichtenberg 94-45 1,817,687 8/31 Heltzel.

7 2,366,715 1/45 French 94-45 JACOB L. NACKENOFF, Primary Examiner. 

11. A MACHINE FOR SMOOTHING THE SURFACE OF A FRESHLY LAID CONCRETE STRIP, CHARACTERIZED BY: (A) A FRAME ADAPTED FOR MOVEMENT OVER SAID STRIP; (B) A PLURALITY OF BELTS MOUNTS CARRIED BY SAID FRAME EACH OF SAID BELT MOUNTS INCLUDING A PIVOT AND A ROCKABALE MEMBER CARRIED BY SAID PIVOT, SAID ROCKABLE MEMBER HAVING A GENERALLY DOWNWARDLY DISPOSED CONVEX ARCUATE SURFACE; (C) A CONCRETE SMOOTHING BELT STRETCHED BETWEEN AND SECURED TO SAID ROCKABLE MEMBERS; AND (D) MEANS INTERCONNECTING SAID ROCKABLE MEMBERS FOR CAUSING THEM TO ROCK ABOUT SAID PIVOT POINTS SUBSTANTIALLY IN UNISON. 